JP3538438B2 - Apparatus for forming excited or unstable gas molecules and methods of using such apparatus. - Google Patents

Abstract

The device comprises a tubular gas passage (5) formed between a peripheral electrode (1) and a dielectric tube (3), on the internal face of which is applied a second electrode (4), the gas moving transversely in the passage (5) between an extended inlet (7) and an extended outlet (8), which are opposite each other, and whose height does not exceed the radial thickness (e) of the passage (5). Application especially to the production of ozone or of treatment (processing) atmospheres. <IMAGE>

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention has an axial tubular gas passage formed between a first electrode and a dielectric coaxial with the first electrode and coupled to a second electrode. And an excited or unstable gas molecule forming device of the type wherein both electrodes are connected to a high voltage high frequency power supply.

[0002]

2. Description of the Prior Art A discharge device of this kind is known from EP 0,160,964, which describes an ozone generator with an axial gas circulation in a gas passage.

[0003]

SUMMARY OF THE INVENTION The object of the present invention is to provide a new device in a compact form which has significantly improved performance, increased reliability and is suitable for many applications.

[0004]

According to one aspect of the present invention, a first electrode surrounds a dielectric and has an elongated gas inlet and a gas outlet parallel to the axis and substantially diametrically opposed, The second electrode is lined on the inner wall of the dielectric.

According to another feature of the invention: the second electrode is formed by metallization of the inner wall of a dielectric, the outer wall of which is coated with an enamel layer; Having a height not exceeding a radial thickness of the gas passage not exceeding .5 mm, the electric field limiting means being adapted to prevent the formation of micro-discharges at the surface at both ends of the dielectric so as to avoid the formation of microdischarges. It is provided near the axial end.

[0006] Such a dielectric barrier discharge (dielectric ba
With a very compact volume, a corona discharge, or a cold discharge, also referred to as a silent discharge or an atmospheric pressure glow discharge, can be realized with a very compact volume, which is 0.3 × 10 ^{5 to} 3 ×. 10 ⁵ Pa pressure,
For example, operating at atmospheric pressure, a few kW of excitable species power (ratio of the total power supplied by the device to the power stored in the gas in the form of excitable species of vibrational quanta) of more than 50%
With R> discharge, it fits more applications with different gases without significant heating of the gas at the outlet.

The apparatus of the present invention is thus suitable for many applications, for the production of ozone, for the supply of CO ₂ mixed lasers, for the formation of a nitriding atmosphere of metals, for the reduction of metal cleaning. Used for atmosphere formation. Other features and advantages of the present invention will become apparent from the following description, given by way of non-limiting example, with reference to the accompanying drawings.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description and drawings, the same or similar components are denoted by the same reference numerals. As shown in FIG. 1, the device according to the invention has a first tubular electrode 1 formed, for example, by the inner surface of a metal block 2,
In the inside, the second electrode 4 is coated on the inner surface by, for example, metal coating.
Are disposed concentrically, for example, a dielectric material tube 3 made of ceramic (for better understanding, FIG.
Is extremely thick.)

[0009] The assembly of the dielectric 3 and the second electrode 4 is therefore on the outside a tubular gas passage 5 together with the first electrode 1 and on the inside is Freon® due to its electronegative nature. This limits the internal space 6 in which the advantageous refrigerant is circulated. The axial extension of the tubular gas passage 5 is up to 1 m, typically up to 50 cm, and its radial thickness e does not exceed 3 mm, typically up to 2.5 mm.

The block 2 has two diametrically opposed longitudinal gaps 7 and 8, each of which is a passage 5 respectively.
An inlet for the gas to be excited therein and an outlet for the gas stream containing excited or unstable molecules are formed. The gaps 7 and 8 extend over the entire axial length of the passage 5 and have a height not exceeding the thickness e, typically approximately equal to the thickness e. The block 2 is advantageously formed around the first electrode 1 with a plurality of conduits 60 through which a coolant, for example water, passes.

The gas inlet 7 is connected to the block 2 and has a homogeneous shape formed in a box 10 having a pipe 11 for supplying a gas having a pressure of 0.3 × 10 ^{5 to} 3 × 10 ⁵ Pa from a gas source 12. It communicates with the chemical chamber 9. Electrodes 1 and 4 are approximately 10k
The actual limit for the power of W is 60 kHz but 15
It is connected to a high-voltage high-frequency generator 13 operating at a frequency of kHz. The gas stream containing the excited species available at outlet 8
Sent to utilization device 14 as seen long ago.

In the embodiment of FIG. 2, an approximately 2 mm thick dielectric tube 3 with an inner metallization 4 constituting a second electrode is seen, the first electrode 1 here forming an inlet 7 and an outlet 8. And a metal tube having a diametrically opposed gap.

The first electrode 1 and the dielectric tube 3 are assembled by a first insulating end piece 15 and a second insulating piece 16 so as to form an airtight coaxial body, and the coaxial body is a parallelepiped main body 2.
0 is slidably and airtightly introduced into the boring portion 17 of the main body 2.
0 is an elongated inlet opening 1 through which the inlet 7 of the first electrode communicates
8 and an elongated outlet opening 1 through which the outlet 8 of the first electrode communicates
9

If the ceramics used in the production of the dielectric tube 3 have good electrical properties suitable for the production of capacitors, they have a grainy surface which, even when polished, causes a reduced behavior under corona discharge. Generally have. To remedy this, according to one aspect of the invention, the outer surface of the dielectric 3 is covered with a thin enamel layer 21 of less than 100 microns, typically about 20 microns.

On the other hand, if the close contact between the inner electrode 4 and the dielectric can avoid micro-discharges along the dielectric, the particular ultra-high power allowed by the dielectric 3-enamel 21 connection However, the problem of significant local enhancement of the electric field at both ends of the inner electrode 4 is also raised.

To remedy this, according to the embodiment of FIG. 2, the inner electrode 4 has a curved, flexible metal contact 2.
Power is supplied by a central tubular conductor 22 connected to opposite ends of the inner electrode 4 by 3 and the outer shape of the metal contact is
Avoiding the discharge in the cooling liquid allows a slow continuous movement of the equipotential formed by the inner electrode, the danger of the discharge is the use of chlorofluorocarbon as a refrigerant due to its strong electronegative nature Significantly reduced.

In fact, according to one aspect of the invention, the tubular conductor 2
2 is a metal block 24 forming a connection to the power supply 13
Traverses a second insulated end piece 16 which is plugged with a radial passage 25 leading into the conductor 22 and in the inner chamber 6 for circulating cooling oil in the inner chamber 6. And a second radial passage 26 leading to the second radial passage.

In a variant, the means for limiting the peak of the electric field at both ends of the high-voltage electrode 4 can be increased by increasing the thickness inward from the end of the dielectric tube 3 or by connecting the end of the dielectric 3 with the first electrode This can be realized by adding a dielectric ring between the opposing ends, the annular surface of the ring being enamelled simultaneously with the dielectric tube 3 and the periphery of the ring being advantageously metallized. is there.

Another variation of these electric field peak limiting means is shown in FIG. 3 and is located on an extension of the end of the high voltage electrode 4 and is of the same type as the outer enamel layer 21 as at the end of the electrode 4. In the form of a metal protective ring 27 covered with an inner enamel layer 28.

As mentioned above, the device according to the invention comprises:
It can be used to create excited species of various gases. When the gas introduced into the device is predominantly nitrogen and has a nitrogen content of typically 78% or more in a gaseous mixture containing oxygen, the device produces mainly nitrogen that is vibrationally excited. Not only does it create molecular and atomic nitrogen excited to the level of A ³ Σg ⁺ .

Vibrationally excited nitrogen has two main uses. That is, the excited nitrogen transfers its energy, and thereby the atomic population (populatio
n) a CO ₂ mixed power laser in which CO ₂ and excited nitrogen are rapidly mixed to create a reverse flow, and nitriding of the metal surface by limited heating of the metal. Nitrogen content plays an important role. Impurities CO ₂ and C that vibrate and reversely excite nitrogen
O, H ₂ and especially H ₂ O must be restricted.

Due to the presence of oxygen in the nitrogen, the output generated decreases almost in proportion to the oxygen concentration. For nitriding,
5% oxygen-containing nitrogen, which is advantageously obtained by permeation or adsorption, can be compromised to the extent that the gas price is significantly reduced without substantially reducing the output of the excited nitrogen compared to the price of pure nitrogen. It is.

The device according to the invention can advantageously be used for the production of ozone from dry air or from pure oxygen.
In the case of oxygen, the device supplies ozone, singlet oxygen and atomic oxygen. The amount of each of these produced species depends on a number of parameters, in particular the temperature of the gas (depending on the gas flow for a given output) and the frequency of the generator.

In fact, the temperature of the gas determines the subsequent destruction rate of the ozone, and thus the transfer of atomic oxygen, and the frequency affects the electron energy and thus the excitation and dissociation of molecular oxygen. In addition to antifouling and disinfecting applications, the products thus generated are used to improve the surface properties of the polymer, especially the adhesion and wettability.

By supplying the apparatus with hydrogen or a hydrogen-based mixture (eg, hydrogen / argon), highly reducing excited or atomic species used, for example, for metal cleaning are created. Although the present invention has been described with respect to particular embodiments, the invention is not limited thereto, but can be made to modifications and variations as will be apparent to those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a device according to the invention.

FIG. 2 is a schematic longitudinal section through a preferred embodiment of the device according to the invention.

FIG. 3 is an enlarged sectional view of one embodiment of a dielectric end according to the present invention.

[Explanation of symbols]

1 First tubular electrode 2,24 metal block 3 Dielectric tube 4 Second inner electrode 5 tubular gas passage e Radial thickness of tubular gas passage 6 internal space (internal room) 7 Gas inlet 8 Gas outlet 9 Homogenization room 10 boxes 11 Gas supply conduit 12 Gas source 13 High voltage high frequency generator 14 Use equipment 15, 16 Insulated end piece 17 Boring 18 Entrance opening 19 Exit opening 20 body 21,28 Enamel layer 22 Central tubular conductor 23 Flexible metal contacts 25,26 radial passage 27 Metal protection ring 60 refrigerant conduit

Continued on the front page (72) Inventor Marie Bruneau France. 78310. Elan Cool. Nouveau Horizon. 13 (72) Inventor Guerlain Daniel, France. 77500 Ciel. Liu Alexandre Bical. Batchiman. 33. Inventor Residance de Vual Fleury (72) Lalke Cristian France. 78280 Guillencourt. Liu Benoit Franchon. 55 (56) References JP-A-60-235702 (JP, A) JP-A-55-75905 (JP, A) JP-A-61-63631 (JP, U) JP-A-4-37865 (JP, Y2) U.S. Pat. No. 4,747,062 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01J 19/08 C01B 13/11 C23C 8/36 H01T 23 / 00 H01J 37/00

Claims (19)

(57) [Claims] An axial tubular gas passage formed between a first electrode (1) and a dielectric (3) coaxial with the first electrode and coupled to a second electrode (4). In a device for forming excited or unstable gas molecules of the type having (5) and both electrodes being connected to a high voltage radio frequency power supply (13), the first electrode (1) surrounds the dielectric (3). And an elongate gas inlet (7) and a gas outlet (8) parallel to the axis and substantially diametrically opposed, wherein the second electrode (4) is lined to the inner wall of the dielectric (3). Features device. 2. The device according to claim 1, wherein the second electrode is formed by metallization of the inner wall of the dielectric. 3. A gas inlet (7) and a gas outlet (8)
Device according to claim 1 or 2, characterized in that it has a height which does not exceed the radial thickness (e) of the gas passage (5). 4. The method according to claim 1, wherein the outer wall of the dielectric comprises a thin enamel layer (2).
4. The device according to claim 1, wherein the device is coated with 1). 5. An electric field limiting means (23; 27) for preventing the formation of a micro discharge at both ends of the dielectric (3),
Device according to any of the preceding claims, characterized in that it is provided near the axial end of the second electrode (4). 6. The device according to claim 5, wherein the electric field limiting means has a contact (23) formed between the second electrode (4) and the central conductor (22). 7. A protection ring (2) formed on a dielectric (3) of an axial extension of a second electrode (4).
Device according to claim 5 or 6, characterized in that it comprises (7). 8. A means for circulating a refrigerant (6; 25, 2)
Device according to any of the preceding claims, characterized in that the (2, 26) is provided in an assembly of a dielectric (3) and a second electrode (4). 9. The two electrodes (1; 4) and the dielectric (3)
Elongated gas inlet opening (18) and gas outlet opening (19)
9. The device according to claim 1, wherein the device is formed in a cylindrical shape that can be inserted into a body having a body. 10. The radial thickness (e) of the gas passage (5).
Does not exceed 2.5 mm. 11. The homogenizing chamber (9) has an inlet passage (18,
7) and a gas supply conduit (1) connected to a gas source (12).
Device according to claim 9, characterized in that it is provided between 1). 12. The device according to claim 11, wherein the gas is air. 13. The device according to claim 11, wherein the gas is oxygen. 14. The apparatus according to claim 11, wherein the gas is nitrogen. 15. The apparatus according to claim 11, wherein the gas is hydrogen. 16. A method according to claim 12 or claim 13.
Use of the apparatus according to claim 1 for producing ozone . 17. The method according to claim 12, wherein:
The use of the apparatus described in the above for supplying a CO ₂ mixing laser.
Usage . 18. An apparatus according to claim 14, wherein said apparatus is a metal nitride atmosphere.
The method of use used to create the atmosphere . 19. The apparatus according to claim 15, wherein the apparatus is a reducing atmosphere.
Usage method used for forming.